I don't know about Nihon Goshin Aikido, thus I can't give any facts about it. As I have written above, I only found about this style through the Web, they claim to be a separate art and their founder didn’t even learn Aikido, for example see the following site:
http://aikidotapes.earthlymarketing.com/content/aboutus.asp
If you have other information, I wouldn’t mind the education.

But I do know About Korindo Aikido History. It is my primary M.A. and Believe me, I have studied it's history quite extensively. I have asked direct students of the Korindo Aikido founder founder - Minoro Hirai Sensei and his sons (by the time I got to Japan, he was already dead) read extensively on this subject and all of those besides my teacher whom have studied at Hirai’s Dojo while the latter was teaching (He was only a beginner back then and as such was mostly supervised by senior students rather then Hirai himself).
Thus I do know for certain Korindo Aikido to be a separate M.A. then Ueshiba Aikido. The confusion relays on the fact that after Hirai had a Ju-Jitsu Dojo, he met with Ueshiba and the latter invited him to his own Dojo in Tokyo, there he was the general affairs manager (mostly an accounting job). Shortly after he was asked to head a new department for practical Ju-Jutsu in the Dai-Nihon-Butokukai organization, the committee he was a chairman of invented the name Aikido (It isn’t Ueshiba’s invention as some believe). In this new capacity he has already left the Ueshiba organization, after the war he was invited to return yet refused since “it wasn’t his way”.
Korindo Aikido stems from other non Daito-ryu roots and has a much more extensive study of traditional weapons in it’s curriculum to state some of the more obvious differences. Having trained some Aikikai Aikido I can state the difference is even greater once one goes for the details.

If what you say is true then I need to look further inot it. I admit I don't know the full history of Korindo Aikido but I did find the Ueshiba connection (like six degrees of seperation!:D ) I will research this further as well and use any more info you have, if you don't mind.

As far as Korindo Aikido there is no point to talk about 6 degrees of separation. It's either one believes Hirai sensei when he says he decided his way was different from Ueshiba's and therefore returned for his own way, or you don't.

One source of info is an interview Pranin from Aikido Journal made with Hirai around 1994.

My teacher says Hirai's relative claim Pranin had "misunderstood" some things, and gave a wrong impression. Especially when he claimed Hirai was Ueshiba's representative in the Dai-Nihon Butokukai. Our dojo joined this organization lately and according to the data he has they have members by their own personal standing, not representatives, and this was even more true around WW2 (the time frame in discussion).

If you read that article you can see Hirai doesn't consider Ueshiba as his teacher. It is evident from the way he is talking about him. Hirai had opened his own club of TJJ long before he met Ueshiba, and was already deep into the evolution of his own M.A. Korindo Aikido's roots aren't in the Daito-ryu Ju-jitsu but in other TJJ systems such as Takenauchi Ryu which Hirai has studied.

I am afraid finding true sources on this subject is difficult if only because of the simple fact it doesn't truly interest any serious researcher (My teacher is intending to publish a book about Korindo Aikido and has the endorsement &amp; permission of the founders sons, it will probably contain even more info and research but would have to be considered biased just like any Ueshiba Aikido students publishing). If you do find anything, please let me know.

(You can find me in cyberkwan as well, under the same username, or use Korindo-Aikido to find my card)